I think a proper way to ask this without the "wtf", would rather be "Why is the mod on a site that requires paid membership, isn't it for free?" (and even this one is insulting, compare this to yours).
In any case, nexus is the best hosting site for mods of almost any popular game out there, and you guessed it, ITS TOTALLY FREE!
Takes less than a min to register and gives you access to more than just PoP, best seconds of your life you'll ever spend.